The present invention relates to a base for dental prosthesis and the like for implantation in bone.
More specifically, the subject of the invention is a base for implantation in bone, including an outer body of rigid material, preferably a biocompatible metallic material, having means for anchoring it to the bony tissue and a cavity in which an inner body, also made of a rigid material, preferably a biocompatible metallic material, with a seat for holding a prosthesis is disposed with the interposition of a layer of resiliently shock-absorbent bonding material; an annular retaining element being connected to the edge of the cavity in the outer body and having an inner edge.
A base for implantation in bone of the type specified above is disclosed in WO-A-8 706 816 (FIG. 4).
In that prior implantation base the inner edge of the annular retaining ring merely overlies the upper portion of the resilient bonding material interposed between the outer body and the inner body. With this construction the resilient bonding material is not sealingly prevented from coming into contact with food and/or mouth fluids which can seep through the interspace between the retaining ring and the inner body and cause a degradation of said resilient bonding material.
Other bases for implantation in bone are described, for example, in U.S. Pat. No. 4 780 080, French patent application 2 580 169, and Dutch patent application 8200711.
The bases for implantation in bone described in these documents have the disadvantage that the resiliently shock-absorbent bonding material interposed between the inner and outer bodies extends to the top of the base and, in the condition of use, is in contact with the surrounding tissue, particularly the gum tissue. This material can thus come into contact with food and various liquids introduced into the mouth and may sooner or later become degraded.